The project is being conducted in collaboration with five Early Head Start programs in the greater Washington, DC area that serve predominantly new immigrant Latino families: Family Services, Inc. The Lourie Center The Rosemount Center United Planning Organization Centro Nia (Washington, DC and Takoma Park, MD) Together we are conducting a randomized trial of home-based Early Head Start services with and without a supplemental, attachment-based parenting program, Dozier's Attachment and Biobehavioral Catch-up (ABC) intervention. The sample will be comprised of 200 Early Head Start families with 6- to 18- month old children. There are three key aims: Aim 1 - Validation: to define criteria for identifying EHS families at risk for experiencing toxic stress and to validate these criteria empirically. Aim 2 - Early Head Start + Parenting: to evaluate through a randomized trial the efficacy and value added of supplementing home-based EHS services with Dozier's ABC program. Aim 3 - Implementation and Sustainability: to evaluate the implementation and sustainability of the ABC program within the EHS context and the linkages between implementation characteristics and program impacts. Key outcomes include observed parenting behaviors and children's stress regulation, assessed both behaviorally and physiologically (e.g., cortisol production, vagal tone). The study's findings will advance the knowledge of how EHS can increase support for early parenting and thus buffer infants and toddlers from toxic stress.